Biological Molecules and Their Functions

Which of the following are the four main types of biological molecules essential for life?

• Carbohydrates, Fats, Vitamins, Minerals

• Proteins, Sugars, Water, Salt

• Carbohydrates, Lipids, Proteins, Nucleic Acids

• Oxygen, Hydrogen, Carbon, Nitrogen

What was a key discovery made by William Prout in the early 1800s?

• He identified the structure of DNA.

• He discovered that stomachs contain hydrochloric acid.

• He developed the theory of evolution.

• He invented the microscope.

What is the primary function of carbohydrates in living organisms?

• To provide genetic instructions.

• To build cell membranes.

• To serve as the main source of energy.

• To transport oxygen in the blood.

What is the difference between a monosaccharide and a disaccharide?

• Monosaccharides are fats, while disaccharides are proteins.

• Monosaccharides are single sugar units, while disaccharides are two sugar units joined together.

• Monosaccharides are complex, while disaccharides are simple.

• Monosaccharides are found in animals, while disaccharides are found in plants.

Which type of carbohydrate is known for forming long chains and is used for energy storage or structural support?

• Monosaccharides

• Disaccharides

• Polysaccharides

• Amino acids

Why do lipids not dissolve in water?

• They are too large.

• Their chemical bonds are mostly non-polar.

• Water is too dense.

• They are lighter than water.

What two main chemical ingredients make up fats?

• Glucose and amino acids

• Glycerol and fatty acids

• Carbohydrates and proteins

• Phosphate groups and steroids

What is the key difference in the chemical structure of a saturated fatty acid compared to an unsaturated fatty acid?

• Saturated fatty acids have more oxygen atoms.

• Unsaturated fatty acids have more carbon atoms.

• Saturated fatty acids have only single bonds between carbon atoms, allowing them to be "saturated" with hydrogen.

• Unsaturated fatty acids are always shorter in length.

What important cellular structure do phospholipids primarily form?

• Cell walls

• Mitochondria

• Cell membranes

• Nucleus

Why are some amino acids called "essential"?

• They are the most common amino acids found in nature.

• The human body cannot produce them and must obtain them from food.

• They are only found in essential foods like fruits and vegetables.

• They are necessary for plant growth, not human health.